Computer data distribution architecture

ABSTRACT

Described are methods, systems and computer readable media for computer data distribution architecture.

This application claims the benefit of U.S. Provisional Application No.62/161,813, entitled “Computer Data System” and filed on May 14, 2015,which is incorporated herein by reference in its entirety.

Embodiments relate generally to computer data systems, and moreparticularly, to methods, systems and computer readable media forcomputer data distribution architecture.

Some conventional computer data systems may maintain data in one or moredata sources that may include data objects such as tables. Theseconventional systems may include clients that independently accesstables from each data source directly. In such data systems, a need mayexist to provide systems and methods for an optimized composite tabledata service providing flexible data routing and caching across thevarious data sources for one or more clients, in order to reduce memoryusage and to enable redundancy, high-availability, scalability, andrule-based data discovery.

Embodiments were conceived in of the above mentioned needs, problemsand/or limitations, among other things.

Some implementations can include a memory-efficient andprocessor-efficient computer system for reliable implementation of atable data cache proxy. The system can comprise a plurality of dataserver computers each being programmed with a table data serviceaccessible via an electronic messaging protocol. The system can alsocomprise a table data cache proxy enabled (TDCP-enabled) server computercoupled to the one or more data server computers, the TDCP-enabledserver computer having a plurality of TDCP clients, the TDCP-enabledserver computer caching data from the plurality of data server computersand aggregating subscriptions of the TDCP clients to the plurality ofdata server computers. The TDCP-enabled server computer can comprise acache memory device having at least a portion being a shared memoryportion. The TDCP-enabled server computer can also comprise one or morehardware processors and a computer readable data storage device coupledto the one or more hardware processors, the computer readable datastorage device having stored thereon software instructions that, whenexecuted by the one or more hardware processors, cause the one or morehardware processors to perform operations. The operations can includereceiving, from a first TDCP client of the plurality of TDCP clients, afirst electronic message requesting table data. The operations can alsoinclude determining whether a shared memory cache stored in the sharedmemory portion of the cache memory device contains a cached copy of therequested table data.

The operations can further include, when the shared memory cachecontains a cached copy of the requested table data, transmitting, to thefirst TDCP client, one or more second electronic messages comprising areference indicating a location where the cached copy is stored in theshared memory portion of the cache memory device in response to thefirst electronic message, the data received from at least one of theplurality of data server computers and stored in the cache memory devicebeing authoritative due to a data model of the plurality of data servercomputers. When the shared memory cache does not contain a cached copyof the requested table data, the operations can include selecting one ormore data server computers from the plurality of data server computersas one or more appropriate data server computers to provide therequested table data. When the shared memory cache does not contain acached copy of the requested table data, the operations can also includetransmitting one or more third electronic messages to the one or moreappropriate data server computers requesting the requested table data.

When the shared memory cache does not contain a cached copy of therequested table data, the operations can further include receiving oneor more fourth electronic messages from the one or more appropriate dataserver computers in response to the third electronic messages. When theshared memory cache does not contain a cached copy of the requestedtable data, the operations can also include filtering the receivedfourth electronic messages and storing a result of the filtering in theshared memory portion of the cache memory device. When the shared memorycache does not contain a cached copy of the requested table data, theoperations can additionally include transmitting, to the first TDCPclient computer, one or more fifth electronic messages comprising areference indicating a location where the result of the filtering isstored in the shared memory portion of the cache memory device inresponse to the first electronic message.

When the shared memory cache does not contain a cached copy of therequested table data, the operations can further include transmitting arequest to subscribe for updates from the one or more appropriate dataserver computers; the operations can also include receiving asubscription update from one or more of the plurality of data servercomputers; and the operations can further include electronicallydistributing the received subscription update to one or more of theplurality of TDCP clients.

Some implementations can include a memory-efficient andprocessor-efficient computer system for reliable implementation of atable data cache proxy. The system can comprise at least one data serverhaving a table data service accessible via an electronic messagingprotocol. The system can also comprise a table data cache proxy enabled(TDCP-enabled) server coupled to the one or more data servers, theTDCP-enabled server caching data from the plurality of data servers andaggregating subscriptions to the plurality of data servers. TheTDCP-enabled server can comprise one or more hardware processors and acomputer readable data storage device coupled to the one or morehardware processors, the computer readable data storage device havingstored thereon software instructions that, when executed by the one ormore hardware processors, cause the one or more hardware processors toperform operations.

The operations can include receiving a first electronic messagerequesting table data. The operations can also include determiningwhether a cache of the TDCP-enabled server contains a cached copy of therequested table data. The operations can further include, when the cacheof the TDCP-enabled server contains a cached copy of the requested tabledata, transmitting one or more second electronic messages providing thecached copy of the requested table data from the cache in response tothe first electronic message, the data received from at least one of theplurality of data servers and stored in the cache being authoritativedue to a data model of the plurality of data servers.

When the cache of the TDCP-enabled server does not contain a cached copyof the requested data: the operations can include determining one ormore appropriate data servers of the plurality of data servers torequest the requested table data from; the operations can also includetransmitting one or more third electronic messages to the one or moreappropriate data servers requesting the requested table data; theoperations can further include receiving one or more fourth electronicmessages from the one or more appropriate servers in response to the oneor more third electronic messages; the operations can also includefiltering the received one or more fourth electronic messages and, basedon a result of the filtering, transmitting one or more fifth electronicmessages providing the requested table data in response to the firstelectronic message.

The first electronic message can be received via an inter processcommunication (IPC) mechanism from a client, the one or more secondelectronic messages can be transmitted to the client via the IPCmechanism, and the one or more fifth electronic messages can betransmitted to the client via the IPC mechanism.

The TDCP-enabled server can comprise a shared memory in which at least aportion of the cache is stored. The one or more second electronicmessages can comprise an indication where the cached copy is stored inthe shared memory of the TDCP-enabled server, and the one or more fifthelectronic messages can comprise indications where the requested tabledata is stored in the shared memory of the TDCP-enabled server.

Additionally or alternatively, first electronic message can be receivedvia a network from a remote client, the one or more second electronicmessages can be transmitted to the remote client via the network, andthe one or more fifth electronic messages can be transmitted to theremote client via the network.

In any of the above-mentioned implementations, the operations can alsoinclude, when the first electronic message requests a block of binarydata, determining whether a future request for another block of binarydata is likely based on a number (and/or pattern) of received requests,and, when the future request is determined to be likely, prefetching theanother block of binary data including transmitting one or more sixthelectronic messages to the one or more appropriate data serversrequesting the another block of binary data.

Some implementations can include a memory-efficient andprocessor-efficient computerized method for reliable implementation of atable data cache proxy. The method can include receiving, at a tabledata cache proxy enabled (TDCP-enabled) server, a first electronicmessage requesting table data, the TDCP-enabled server being coupled toone or more data servers having a table data service accessible via anelectronic messaging protocol, the TDCP-enabled server caching data fromthe one or more data servers and aggregating subscriptions to the one ormore data servers. The method can also include determining whether acache of the TDCP-enabled server contains a cached copy of the requestedtable data. The method can further include, when the cache of theTDCP-enabled server contains a cached copy of the requested table data,transmitting one or more second electronic messages providing the cachedcopy of the requested table data from the cache in response to the firstelectronic message, the data received from at least one of the one ormore data servers and stored in the cache being authoritative due to adata model of the one or more data servers.

When the cache of the TDCP-enabled server does not contain a cached copyof the requested data: the method can include determining one or moreappropriate data servers of the one or more data servers to request therequested table data from; the method can also include transmitting oneor more third electronic messages to the one or more appropriate dataservers requesting the requested table data; the method can furtherinclude receiving one or more fourth electronic messages from the one ormore appropriate servers in response to the one or more third electronicmessages; and the method can also include filtering the received one ormore fourth electronic messages and, based on a result of the filtering,transmitting one or more fifth electronic messages providing therequested table data in response to the first electronic message.

The method can include determining whether a future request for anotherblock of binary data is likely based on a number (and/or pattern) ofreceived requests; and when the future request is determined to belikely, the method can include prefetching the another block of binarydata including transmitting one or more sixth electronic messages to theone or more appropriate data servers requesting the another block ofbinary data.

When the cache of the TDCP-enabled server does not contain a cached copyof the requested data: the method can include transmitting a request tosubscribe for updates from one or more appropriate data servers; themethod can also include receiving a subscription update from one or moreof the one or more data servers; and the method can further includeelectronically distributing the received subscription update to one ormore subscribers of the TDCP-enabled server.

Some implementations can include a nontransitory computer readablemedium having stored thereon software instructions that, when executedby one or more processors, cause the one or more processors to performoperations. The operations can include receiving, at a table data cacheproxy enabled (TDCP-enabled) server, a first electronic messagerequesting table data, the TDCP-enabled server being coupled to one ormore data servers having a table data service accessible via anelectronic messaging protocol, the TDCP-enabled server caching data fromthe one or more data servers and aggregating subscriptions to the one ormore data servers. The operations can also include determining whether acache of the TDCP-enabled server contains a cached copy of the requestedtable data. When the cache of the TDCP-enabled server contains a cachedcopy of the requested table data, the operations can includetransmitting one or more second electronic messages providing the cachedcopy of the requested table data from the cache in response to the firstelectronic message, the data received from at least one of the one ormore data servers and stored in the cache being authoritative due to adata model of the one or more data servers. When the cache of theTDCP-enabled server does not contain a cached copy of the requesteddata: the operations can include determining one or more appropriatedata servers of the one or more data servers to request the requestedtable data from; the operations can also include transmitting one ormore third electronic messages to the one or more appropriate dataservers requesting the requested table data; the operations can furtherinclude receiving one or more fourth electronic messages from the one ormore appropriate servers in response to the one or more third electronicmessages; and the operations can also include filtering the received oneor more fourth electronic messages and, based on a result of thefiltering, transmitting one or more fifth electronic messages providingthe requested table data in response to the first electronic message.

The operations can include determining whether a future request foranother block of binary data is likely based on a number of receivedrequests, and when the future request is determined to be likely,prefetching the another block of binary data including transmitting oneor more sixth electronic messages to the one or more appropriate dataservers requesting the another block of binary data.

In any of the above-mentioned implementations, the first electronicmessage can request data from a data block and comprise a minimumresponse length, and when additional data above the minimum responselength is available within the block, the additional data is included inresponse to the first electronic message to prevent redundant subsequentrequests.

In any of the above-mentioned implementations, the first electronicmessage can be one of: a table location discovery request requesting alist of table locations for a given table key, the table key uniquelyidentifying a table; a table location metadata retrieval requestrequesting table-location-level metadata including the size of a table;a column location metadata retrieval request requestingcolumn-location-level metadata, wherein column data is laid out in anoptimized data layout to enable high performance data access, thecolumn-location-level metadata including information indicating theoptimized data layout; a column file size retrieval request requestingthe size of a column file; and a column file data retrieval requestrequesting at least a portion of a block of binary data from a columnfile.

In any of the above-mentioned implementations, the at least one dataserver can be a plurality of data servers comprising at least two datasources providing the same data; and the TDCP-enabled server can beconfigured to reconnect to any of the data servers, and uponreconnection any in-progress requests are re-sent and any subscriptionsare renewed.

In any of the above-mentioned implementations, the one or more dataservers can comprise a plurality of data servers, and, when the firstelectronic message requests one or more data locations, the filteringcan comprise combining at least a portion of each of two or more of theone or more fourth electronic messages to create a composite of datafrom two or more of the plurality of data servers as the result of thefiltering.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram of an example computer data system showing anexample data. distribution configuration in accordance with someimplementations.

FIG. 2 is a diagram of an example computer data system showing anexample administration/process control arrangement in accordance withsome implementations.

FIG. 3A is a diagram of an example query server host in accordance withsome implementations.

FIG. 3B is a diagram of an example query server host in accordance withsome implementations.

FIG. 4 is a diagram of an example computer data system and network 400showing an example data distribution configuration in accordance withsome implementations.

FIG. 5 is a flowchart of an example method of processing a TDCPcomposite table data service request in accordance with someimplementations.

FIG. 6 is a flowchart of an example method of processing a tablelocation discovery request by a TDCP server in accordance with someimplementations.

FIG. 7 is a flowchart of an example method of processing a tablelocation metadata retrieval request by a TDCP server in accordance withsome implementations.

FIG. 8 is a flowchart of an example method of processing a columnlocation metadata retrieval request by a TDCP server in accordance withsome implementations.

FIG. 9 is a flowchart of an example method of processing a column filesize retrieval request by a TDCP server in accordance with someimplementations.

FIG. 10 is a flowchart of an example method of processing a column filedata retrieval request by a TDCP server in accordance with someimplementations.

FIG. 11 is a diagram of an example computing device configured for tabledata cache proxy (TDCP) processing in accordance with at least oneimplementation.

DETAILED DESCRIPTION

Reference may be made herein to the Java programming language, Javaclasses, Java bytecode and the Java Virtual Machine (JVM) for purposesof illustrating example implementations. It will be appreciated thatimplementations can include other programming languages (e.g., groovy,Scala, R, Go, etc.), other programming language structures as analternative to or in addition to Java classes (e.g., other languageclasses, objects, data structures, program units, code portions, scriptportions, etc.), other types of bytecode, object code and/or executablecode, and/or other virtual machines or hardware implemented machinesconfigured to execute a data system query.

FIG. 1 is a diagram of an example computer data system and network 100showing an example data distribution configuration in accordance withsome implementations. In particular, the system 100 includes anapplication host 102, a periodic data import host 104, a query serverhost 106, a long-term file server 108, and a user data import host 110.While tables are used as an example data object in the descriptionbelow, it will be appreciated that the data system described herein canalso process other data objects such as mathematical objects e.g., asingular value decomposition of values in a given range of one or morerows and columns of a table), TableMap objects, etc. A TableMap objectprovides the ability to lookup a Table by some key. This key representsa unique value (or unique tuple of values) from the columns aggregatedon in a byExternal( ) statement execution, for example. A TableMapobject is can be the result of a byExternal( ) statement executed aspart of a query. It will also be appreciated that the configurationsshown in FIGS. 1 and 2 are for illustration purposes and in a givenimplementation each data pool (or data store) may be directly attachedor may be managed by a file server.

The application host 102 can include one or more application processes112, one or more log files 114 (e.g., sequential, row-oriented logfiles), one or more data log milers 116 and a multicast key-valuepublisher 118. The periodic data import host 104 can include a localtable data server, direct or remote connection to a periodic table datastore 122 (e.g., a column-oriented table data store) and a data importserver 120. The query server host 106 can include a multicast key-valuesubscriber 126, a performance table logger 128, local table data store130 and one or more remote query processors (132, 134) each accessingone or more respective tables (136, 138). The long-term file server 108can include a long-term data store 140. The user data import host 110can include a remote user table server 142 and a user table data store144. Row-oriented log files and column-oriented table data stores arediscussed herein for illustration purposes and are not intended to belimiting. It will be appreciated that log files and/or data stores maybe configured in other ways. In general, any data stores discussedherein could be configured in a manner suitable for a contemplatedimplementation.

In operation, the input data application process 112 can be configuredto receive input data from a source (e.g., a securities trading datasource), apply schema-specified, generated code to format the loggeddata as it's being prepared for output to the log file 114 and store thereceived data in the sequential, row-oriented log file 114 via anoptional data logging process. In some implementations, the data loggingprocess can include a daemon, or background process task, that isconfigured to log raw input data received from the application process112 to the sequential, row-oriented log files on disk and/or a sharedmemory queue (e.g., for sending data to the multicast publisher 118).Logging raw input data to log files can additionally serve to provide abackup copy of data that can be used in the event that downstreamprocessing of the input data is halted or interrupted or otherwisebecomes unreliable.

A data log tailer 116 can be configured to access the sequential,row-oriented log file(s) 114 to retrieve input data logged by the datalogging process. In some implementations, the data log tailer 116 can beconfigured to perform strict byte reading and transmission (e.g., to thedata import server 120). The data import server 120 can be configured tostore the input data into one or more corresponding data stores such asthe periodic table data store 122 in a column-oriented configuration.The periodic table data store 122 can be used to store data that isbeing received within a time period (e.g., a minute, an hour, a day,etc.) and which may be later processed and stored in a data store of thelong-term file server 108. For example, the periodic table data store122 can include a plurality of data servers configured to store periodicsecurities trading data according to one or more characteristics of thedata (e.g., a data value such as security symbol, the data source suchas a given trading exchange, etc.).

The data import server 120 can be configured to receive and store datainto the periodic table data store 122 in such a way as to provide aconsistent data presentation to other parts of the system.Providing/ensuring consistent data in this context can include, forexample, recording logged data to a disk or memory, ensuring rowspresented externally are available for consistent reading (e.g., to helpensure that if the system has part of a record, the system has all ofthe record without any errors), and preserving the order of records froma given data source. If data is presented to clients, such as a remotequery processor (132, 134), then the data may be persisted in somefashion (e.g., written to disk).

The local table data server 124 can be configured to retrieve datastored in the periodic table data store 122 and provide the retrieveddata to one or more remote query processors (132, 134) via an optionalproxy (e.g., table data cache proxy (TDCP) 394 and/or 404 as shown inFIG. 3 and FIG. 4, respectively). Remote query processors (132, 134) canalso receive data from DIS 120 and/or LTDS 124 via the proxy.

The remote user table server (RUTS) 142 can include a centralizedconsistent data writer, as well as a data server that providesprocessors with consistent access to the data that it is responsible formanaging. For example, users can provide input to the system by writingtable data that is then consumed by query processors.

The remote query processors (132, 134) can use data from the data importserver 120, local table data server 124 and/or from the long-term fileserver 108 to perform queries. The remote query processors (132, 134)can also receive data from the multicast key-value subscriber 126, whichreceives data from the multicast key-value publisher 118 in theapplication host 102. The performance table logger 128 can logperformance information about each remote query processor and itsrespective queries into a local table data store 130. Further, theremote query processors can also read data from the RUTS, from localtable data written by the performance logger, or from user table dataread over NFS, for example.

It will be appreciated that the configuration shown in FIG. 1 is atypical example configuration that may be somewhat idealized forillustration purposes. An actual configuration may include one or moreof each server and/or host type. The hosts/servers shown in FIG. 1(e.g., 102-110, 120, 124 and 142) may each be separate or two or moreservers may be combined into one or more combined server systems. Datastores can include local/remote, shared/isolated and/or redundant. Anytable data may flow through optional proxies indicated by an asterisk oncertain connections to the remote query processors (e.g., table datacache proxy (TDCP) 392 or 404 as shown in FIG. 3B and FIG. 4,respectively). Also, it will be appreciated that the term “periodic” isbeing used for illustration purposes and can include, but is not limitedto, data that has been received within a given time period (e.g.,millisecond, second, minute, hour, day, week, month, year, etc.) andwhich has not yet been stored to along-term data store (e.g., 140).

FIG. 2 is a diagram of an example computer data system 200 showing anexample administration/process control arrangement in accordance withsome implementations. The system 200 includes a production client host202, a controller host 204, a GUI host or workstation 206, and queryserver hosts 208 and 210. It will be appreciated that there may be oneor more of each of 202-210 in a given implementation.

The production client host 202 can include a batch query application 212(e.g., a query that is executed from a command line interface or thelike) and a real time query data consumer process 214 (e.g., anapplication that connects to and listens to tables created from theexecution of a separate query). The batch query application 212 and thereal time query data consumer 214 can connect to a remote querydispatcher 222 and one or more remote query processors (224, 226) withinthe query server host 1 208.

The controller host 204 can include a persistent query controller 216configured to connect to a remote query dispatcher 232 and one or moreremote query processors 228-230. In some implementations, the persistentquery controller 216 can serve as the “primary client” for persistentqueries and can request remote query processors from dispatchers, andsend instructions to start persistent queries. For example, a user cansubmit a query to 216, and 216 starts and runs the query every day. Inanother example, a securities trading strategy could be a persistentquery. The persistent query controller can start the trading strategyquery every morning before the market opened, for instance. It will beappreciated that 216 can work on times other than days. In someimplementations, the controller may require its own clients to requestthat queries be started, stopped, etc. This can be done manually, or byscheduled (e.g., cron jobs). Some implementations can include “advancedscheduling” (e.g., auto-start/stop/restart, time-based repeat, etc.)within the controller.

The GUI/host workstation can include a user console 218 and a user queryapplication 220. The user console 218 can be configured to connect tothe persistent query controller 216. The user query application 220 canbe configured to connect to one or more remote query dispatchers (e.g.,232) and one or more remote query processors (228, 230).

FIG. 3A is a diagram of an example query server host 320 (e.g., asdescribed at 208, 210, and/or 106) in accordance with at least oneembodiment. Query server host 320 can include a processor 324, a highspeed memory e.g., RAM) 326, another high speed memory (e.g., shared RAMwith RQP and TDP) 336. Query server host 320 can access a medium accessspeed memory 346 (e.g., RAM managed by another host (actual or virtual)such as, for example, an intraday server (e.g., DIS 120 or LTDS 124))and a slow access speed storage 355 (e.g., a file server with hard drivesuch as, for example, long term file server 108).

In operation, processor 324 can execute remote query processor 322 whichstores/accesses data in high speed memory 326, high speed memory 336,medium access speed memory 346, and slow access speed storage 354. Highspeed memory 326 and high speed memory 336 can be memory on the same ordifferent memory devices.

High speed memory 326 can contain one or more query update graphs 328,one or more table indexes 330, in memory data 332, and recent data cache334. High speed memory 326 can request and retrieve data from one ormore slow access speed storages 355 and/or from high speed memory 336.

High speed memory 336 can be memory that is shared with one or moreremote query processors 322 and/or one or more table data cache proxies(e.g., TDCP 392 and 404, as shown in FIG. 3 and FIG. 4 respectively).High speed memory 336 can contain one or more data columns, for example,a symbol column data 338, a date column data 340, a time column data342, and a quote column data 344. High speed memory 336 can exchangedata with remote query processor 322, high speed memory 326, and/ormedium access speed memory 346, and can request and receive data fromslow access speed storage 355.

Medium access speed memory 346 can contain one or more data columns, forexample, symbol column data 348, a date column data 350, a time columndata 352, and a quote column data 354. Medium access speed memory 346can exchange data with high speed memory 336 and can transmit data to aslow access speed storage 355. In some embodiments, medium access speedmemory 346 is RAM that resides on a remote host, administered by aremote process (e.g., DIS 120, LTDS 124, or RUTS 142).

Slow access speed storage 355, for example, a file server with one ormore hard drives, can contain persistent column data, for example, asymbol column 358, a date column 360, a time column 362, and a quotecolumn 364. The one or more persisted column data 358-364 can be copiedinto medium speed solid state storage 356, for example, flash, toprovide faster access for more frequently accessed data. ho someembodiments, slow access speed storage 355 is used by long-term fileserver 108.

In some embodiments, remote query processor 322 can access a tablehaving column data of two or more columns of the table stored indifferent memory devices and/or data servers. In some such embodiments,column data of a column (i.e., different rows or groups of rows) canalso be stored in different memory devices and/or data servers.Processor 322 can store/access identifiers indicating where column dataof the columns/rows is stored. Processor 322 can also store/access oneor more table indexes associated with the table that identify for thattable the valid portion(s) of the data referenced by the locationidentifier e.g., the portions of the data which correspond to the rowsof that table). For example, in some embodiments, a first portion ofcolumn data can be stored in shared memory with TDCP 336, a secondportion of column data can be stored in medium speed memory 346, and athird portion of column data can be stored in slow speed storage 355,for the same or different columns of a table.

FIG. 3B is a diagram of an example query server host 370 (e.g., asdescribed at 320, 208, 210, and/or 106) in accordance with at least oneembodiment. Query server host 370 can contain one or more remote queryprocessors (372, 374, 376) associated with one or more table data cacheproxy clients (378, 380, 382), a shared memory 384 (e.g., as describedat 336) that can exchange data (386, 388, 390) with table data cacheproxy clients (378, 380, 382), and one or more table data cache proxies392 that can exchange data with shared memory 384.

FIG. 4 is a diagram of an example computer data system and network 400showing an example data distribution configuration in accordance withsome implementations. System 400 includes local table data server (LTDS)124, data import server (DIS) 120, remote user table server (RUTS) 142,and a host 402 (e.g., query server host 106, 208, 210, 320, and/or 370).Host 402 includes table data cache proxy (TDCP) 404, one or more remotequery processors (RQP) 412/414, and one or more TDCP clients 408/410.TDCP includes a cache 406. In operation, each RQP 412/414 transmits datato and receives data from TDCP 404 via a corresponding one of TDCPclients 408/410, and TDCP 404 transmits data to and receives data fromeach of LTDS 124, 120, and RUTS 142.

In some embodiments, TDCP 404 exports a composite table data servicecomposed of multiple filtered remote table data services, in someembodiments, each of data sources 120, 124, and 142 exports a table dataservice via a messaging protocol and TDCP 404 is configured to export acomposite table data service composed of the table data services of thedata sources via a messaging protocol. The composite table data serviceof TDCP 404 can be composed of the services of data sources 120, 124,and 142 that are filtered and/or combined at a table-location level. Agiven “location” for a table may be provided by a single, non-compositeservice, but a client-visible table might be composed of locations frommultiple underlying sources and the composite table data service of TDCP404 provides data from the multiple underlying sources to a client(e.g., RQP 412/414 via TDCP clients 408/410), filtered and/or combinedas appropriate.

In some embodiments, TDCP 404 is coupled to multiple of one or more ofthe different types of data sources 120, 124, and 142. In some suchembodiments, the multiple data sources can provide the same data. Thecomposite table data service of TDCP 404 can be configured to reconnectto any of the data sources that can provide the same data, and uponreconnection any in-progress requests are re-sent and any subscriptionsare renewed.

In some embodiments, LTDS 124 provides access to un-merged real-timedata from previous time periods (e.g., from the same storage systems towhich current-period data is persisted by DIS 120). In some suchembodiments, LTDS 124 can be used as a stop-gap (i.e., alternate datasource) when issues prevent timely completion of the merge operationsthat transform, validate, and promote periodic data.

In some embodiments, the messaging protocol is identical for datasources 120, 124, and 142. In some such embodiments, the messagingprotocol for TDCP 404 is identical to that of the data sources. In someembodiments, the messaging protocol of the data sources 120, 124, and142 and/or the messaging protocol of TDCP 404 is built on top of one ormore other networking protocols (e.g., TCP/IP).

In some embodiments, TDCP 404 is configured to serve as an aggregator ofsubscriptions by RQP 412/414 to the same metadata updates and/orrequests for individual data and/or metadata items. TDCP 404 isconfigured to cache data and/or metadata received from data servers 120,124, and 142 in cache 406.

In some embodiments, cache 406 comprises data blocks indexed by{{namespace, table name, table type}, {internal partition, columnpartition}, {column name, column file type, offset}} or, more generally,{table key}, {table location key}, {column block key}. Data blocks incache 406 may be evicted (e.g., based on a modified LRU policy) at anytime when they are not actively in-use. If more data becomes available(e.g., as implied by table size change notifications), the missingregion of an already-cached data block can be read when a clientrequests the block in question. Successful data block read requestsprovide at least as much data as requested, but may provide more if theblock has grown and the source can provide an additional suffix.

In some embodiments, cache 406 is indexed per-source. Each bottom-leveltable data service uses either the filesystem (which may be remote orlocal) or at most one actively-connected server, and maintains its ownindex of which location data it has. All caches within a given processgenerally share the same pool of free/managed data block memory-space,but this is configurable. The engine code deals with table locations,which have location-level metadata, per-column location-level metadata,and buffer stores associated with each relevant column file. The bufferstore handles block indexing and presents the engine with byte-orientedaccess, which is then translated to cell-oriented access by anintermediate level of the engine code.

In embodiments, system 400 is configured such that TDCP 404 isauthoritative for data stored in cache 406 from at least one of datasources 120, 124, and 142. Cache 406 includes data requested by theclients of TDCP 404, and different TDCPs with different attachedclients/workloads will have different caches. Additionally, because ofthe underlying model for data updates used by data sources such as 120and 124 in some embodiments (repeatable reads by virtue of append-onlydata changes, in the real-time system), if cache 406 has a data blockfrom one of those data sources, it has the correct (i.e., authoritative)data for that data block. If it has a partial data block, the range thatit has is correct data for that range. TDCP 404 therefore doesn't haveto worry about having its data invalidated by upstream changes.

In some embodiments, connections between data sources 120, 124, and 142and TDCP 404 are authenticated (e.g., using ACL permissions) and/orencrypted.

In some embodiments, TDCP 404 can communicate with TDCP clients 408-410via an inter-process communication (IPC) mechanism (e.g., sockets,shared memory, memory mapped files, message passing, pipes, and/ormessage queues). For example, cache 406 can be stored in shared memory(e.g., shared memory 384 as shown in FIG. 3B). In some embodiments, theshared memory is System V IPC shared memory accessed with the various“shm_system” calls. In some embodiments, mixed IPC mechanisms may beused. For example, TDCP 404 can transmit data to one or more TDCPclients on a different host (actual or virtual) via one IPC mechanism(e.g., a socket/network) and provide data to one or more different TDCPclients via a different IPC mechanism (e.g., shared memory). In anotherexample, TDCP 404 can communicate with data sources 120/124/142 using anIPC mechanism that is the same or different than that used forcommunications between TDCP 404 and TDCP clients 408-410.

Although not shown, in some embodiments, TDCP clients 408-410 and RQP412-414 can be on a separate host (actual or virtual). In some suchembodiments, data can be transmitted between TDCP 404 and TDCP clients408-410 via a network.

In some embodiments, data may be transmitted between TDCP 404, datasources 120/124/142, TDCP clients 408-410, and RQP 412-414 using singleand/or multipart messages.

In some embodiments, TDCP 404 and/or TDCP clients 408-410 maintain aseparate cache (or a separate portion of the cache) for each RQP412-414. In other embodiments, TDCP 404 and/or TDCP clients 408-410 canmaintain separate and/or shared caches for RQP 412-414. (e.g., sharing acache between two or more RQPs while maintaining a separate cache for adifferent RQP, or sharing one cache for all RQPs).

FIG. 5 is a flowchart of an example method 500 of processing a TDCPcomposite table data service request in accordance with someimplementations. Processing begins at 502, where a remote queryprocessor (RQP) (e.g., remote query processors 132-134, 322, 372-376, or412-414 shown in FIG. 1, FIG. 3A, FIG. 3B, and FIG. 4, respectively)requests table (data and/or metadata) from a TDCP server (e.g., as shownin FIG. 3B or FIG. 4). Processing continues to 504.

At 504, the TDCP determines whether the requested table data/metadata isin the TDCP local state (or cache such as, for example, shared RAM 336,shared memory 384, or cache 406 shown in FIG. 3A, FIG. 3B, and FIG. 4,respectively). If so, processing continues to 510; otherwise, processingcontinues to 506.

At 506 the TDCP requests the latest state and subscribes to updates forthe table from one or more appropriate data servers (e.g., LTDS 124, DIS120, and/or RUTS 142 shown in FIG. 1 and FIG. 4). In some embodiments,the TDCP is coupled to multiple data servers (e.g., LTDS 124, DIS 120,and/or RUTS 142) and the TDCP selects one or more of the multiple dataservers as the appropriate data servers for the request received at 502.In some embodiments, the one or more appropriate data servers can beselected based on a table type indicated in the request received at 502(e.g., by determining which of the data servers match the table type andselecting those that match). In some embodiments, additional user tablescan come from RUTS 142 and one more “user” filesystems mounted over NFS,performance log tables can be from locally-mounted filesystems, all ofwhich may have independent services that can be composed by the TDCP andselected by the TDCP as one of the appropriate data servers.

At 508, the appropriate data servers distribute latest table state tothe TDCP. The latest table state is received in response to therequest(s) made by the TDCP at 506 and is stored in the TDCP cache.Processing continues to 510.

At 510, the TDCP filters/distributes the latest table state to the RQP.The latest table state can be filtered based on rules such as, forexample, rules defining where data should come from (e.g., which datasource is authoritative). Filtering can include removing metadatachanges that aren't important to certain classes of downstream consumers(e.g., some TDCPs or RQPs might only want size changes, and/or might notwant modifications after a certain time of day, and/or might not need tosee all metadata fields). Additionally or alternatively, the TDCP cancombine data related to two or more “downstream” table locations (withthe same keys), and the filtering can include coalescing changes andonly advertising them when (for example) a threshold (more than one, orall) number of the data sources being combined had advertised the samething, thereby increasing the likelihood that data can be re-readpromptly in the event of a subset of the data sources crashing orbecoming partitioned away.

In some embodiments, the TDCP can be configured to optimize theperformance of computer data access when multiple data servers eachprovide access to the same data by requesting the latest table statefrom two or more of the multiple data servers at 506 and by filteringthe received/cached table state to generate a complete, non-duplicativecomposite table state that includes data/metadata from two or more ofthe multiple data servers. In such embodiments, the table state caninclude table locations and the TDCP can filter table locations to bedistributed to the RQP to interleave table locations from the multipledata servers, thereby distributing subsequent data access across themultiple data servers. Processing continues to 512.

At 512, the TDCP listens to table updates from the data servers.Listening to table updates can include listening to table updates fromdata servers to which the TDCP has subscribed for updates. Processingcontinues to 514.

At 514, the TDCP distributes updates to subscribing RQP. The TDCP canoperate as an aggregator of subscriptions for multiple RQP and uponreceiving an update the TDCP can distribute the update to thesubscribing RQP. For example, although not shown, two different RQP cansubscribe to the TDCP to receive updates. In some embodiments, theupdates can be filtered as described above at 510 before beingdistributed to subscribing RQP.

It will be appreciated that, although not shown, the subscribing RQP cancancel their subscription to stop receiving updates from the TDCP, thatall subscriptions are cancelled for an RQP that disconnects, and thatthe TDCP may cancel its own data subscriptions and/or discard data it nolonger needs for any RQP.

It will also be appreciated that 502-514 may be repeated in whole or inpart. For example, 512-514 may be repeated to continuously provide tablelocation updates to the subscribing RQP.

FIG. 6 is a flowchart of an example method 600 of processing a tablelocation discovery request by a TDCP server (e.g., as shown in FIG. 3Bor FIG. 4) in accordance with some implementations. Processing begins at602, where a remote query processor (RQP) (e.g., remote query processors132-134, 322, 372-376, or 412-414 shown in FIG. 1, FIG. 3A, FIG. 3B, andFIG. 4, respectively) requests table locations for a given table keyfrom the TDCP. The table key can comprise a namespace, a table name, anda table type (e.g. user/system, periodic/historical). In someembodiments, table locations are keyed by path information such as, forexample, internal partition and column partition. Processing continuesto 604.

At 604, the TDCP determines whether the requested data is in the TDCPlocal state (or cache such as, e.g., shared RAM 336, shared memory 384,or cache 406 shown in FIG. 3A, FIG. 3B, and FIG. 4, respectively). Ifso, processing continues to 610; otherwise, processing continues to 606.

At 606 the TDCP requests table locations for the given table key fromone or more appropriate data servers (e.g., LTDS 124, DIS 120, and/orRUTS 142 shown in FIG. 1 and FIG. 4) and optionally subscribes forupdates. In some embodiments, the TDCP is coupled to multiple dataservers (e.g., LTDS 124, DIS 120, and/or RUTS 142) and the TDCP selectsone or more of the multiple data servers as the appropriate data serversfor the request received at 602. In some embodiments, the one or moreappropriate data servers can be selected based on the table typeindicated by the table key (e.g., by determining which of the dataservers match the table type and selecting those that match).

At 608, the TDCP receives table locations. The table locations arereceived in response to the request(s) made by the TDCP at 606 and arestored in the TDCP cache. Processing continues to 610.

At 610, the TDCP filters/distributes the table locations to the RQP. Thetable locations can be filtered based on rules such as, for example,rules defining where data should come from (e.g., which data source isauthoritative). In some embodiments, the TDCP can be configured tooptimize the performance of computer data access when multiple dataservers each provide access to the same data by requesting tablelocations from two or more of the multiple data servers at 606 and byfiltering the received/cached table locations to generate a complete,non-duplicative set of table locations that includes locations from twoor more of the multiple data servers, in such embodiments, the TDCP can,for example, filter the table locations to be distributed to the RQP tointerleave table locations from the multiple data servers, therebydistributing subsequent data access across the multiple data servers.

Additionally or alternatively, the TDCP can combine data received fromdata servers that provide access to the same data (e.g., by combiningdifferent portions to generate a complete, non-duplicative set asdiscussed above, by combining all data, or by including data receivedfrom one of the data servers and excluding data received from the otherdata servers), and the filtering can include coalescing changes and onlyadvertising them when (for example) a threshold (more than one, or all)number of the data sources being combined had advertised the same thing,thereby increasing the likelihood that data can be re-read promptly inthe event of a subset of the data sources crashing or becomingpartitioned away. Processing continues to 612.

At 612, the TDCP listens to table updates from the data servers.Listening to table updates can include listening to table updates fromdata servers to which the TDCP has subscribed for updates. Processingcontinues to 614.

At 614, the TDCP distributes updates to subscribing RQP. The TDCP canoperate as an aggregator of subscriptions for multiple RQP and uponreceiving an update the TDCP can distribute the update to thesubscribing RQP. For example, although not shown, two different RQP cansubscribe to the TDCP to receive updates to table locations. In someembodiments, the updates can be filtered as described above at 610before being distributed to subscribing RQP.

It will be appreciated that, although not shown, the subscribing RQP cancancel their subscription to stop receiving updates from the TDCP, thatall subscriptions are cancelled for an RQP that disconnects, and thatthe TDCP may cancel its own data subscriptions and/or discard data it nolonger needs for any RQP.

It will also be appreciated that 602-614 may be repeated in whole or inpart. For example, 612-614 may be repeated to continuously provide tablelocation updates to the subscribing RQP.

FIG. 7 is a flowchart of an example method 700 of processing a tablelocation metadata retrieval request by a TDCP server (e.g., as shown inFIG. 3B or FIG. 4) in accordance with some implementations. Processingbegins at 702, where a remote query processor (RQP) remote queryprocessors 132-134, 322, 372-376, or 412-414 shown in FIG. 1, FIG. 3A,FIG. 3B, and FIG. 4, respectively) requests table location metadata fora given table from the TDCP. The table location metadata can comprisesize, modification time, validation status and validation completiontime (e.g., validation being a process of ensuring that the data haspassed proper quality checks), schema version used to generate the data,code version used to generate the data, user identifying information,and other metadata. Table location metadata can also include an “isvalid” flag or an “is finished” flag to indicate that the data has beenvalidated (e.g., that the data has passed proper quality checks).Processing continues to 704.

At 704, the TDCP determines whether the requested table locationmetadata is in the TDCP local state (or cache such as, e.g., shared RAM336, shared memory 384, or cache 406 shown in FIG. 3A, FIG. 3B, and FIG.4, respectively). If so, processing continues to 710; otherwise,processing continues to 706.

At 706 the TDCP requests table location metadata from one or moreappropriate data servers (e.g., LTDS 124, DIS 120, and/or RUTS 142 shownin FIG. 1 and FIG. 4) and subscribes for updates. In some embodiments,the TDCP is coupled to multiple data servers (e.g., LTDS 124, DIS 120,and/or RUTS 142) and the TDCP selects one or more of the multiple dataservers as the appropriate data servers for the request received at 702.In some embodiments, the one or more appropriate data servers can beselected based on a table type and/or table location indicated in therequest received at 702 (e.g., by determining which of the data serversmatch the table type and/or table location and selecting those thatmatch).

At 708, the TDCP receives table location metadata. The table locationmetadata is received in response to the request(s) made by the TDCP at706 and are stored in the TDCP cache. Processing continues to 710.

At 710, the TDCP filters/distributes the table location metadata to theRQP. The table location metadata can be filtered based on rules such as,for example, rules defining where data should come from (e.g., whichdata source is authoritative). Filtering can include removing metadatachanges that aren't important to certain classes of downstream consumers(e.g., some TDCPs or RQPs might only want size changes, and/or might notwant modifications after a certain time of day, and/or might not need tosee all metadata fields). Additionally or alternatively, the TDCP cancombine data related to two or more “downstream” table locations (withthe same keys), and the filtering can include coalescing changes andonly advertising them when (for example) a threshold (more than one, orall) number of the data sources being combined had advertised the samething, thereby increasing the likelihood that data can be re-readpromptly in the event of a subset of the data sources crashing orbecoming partitioned away. Processing continues to 712.

At 712, the TDCP listens to table updates from the data servers.Listening to table updates can include listening to table updates fromdata servers to which the TDCP has subscribed for updates. Processingcontinues to 714.

At 714, the TDCP distributes updates to subscribing RQP. The TDCP canoperate as an aggregator of subscriptions for multiple RQP and uponreceiving an update the TDCP can distribute the update to thesubscribing RQP. For example, although not shown, two different RQP cansubscribe to the TDCP to receive updates to table location metadata. Insome embodiments, the updates can be filtered as described above at 710before being distributed to subscribing RQP.

It will also be appreciated that, although not shown, the subscribingRQP can cancel their subscription to stop receiving updates from theTDCP, that all subscriptions are cancelled for an RQP that disconnects,and that the TDCP may cancel its own data subscriptions and/or discarddata it no longer needs for any RQP.

It will also be appreciated that 702-714 may be repeated in whole or inpart. For example, 712-714 may be repeated to continuously provide tablelocation metadata updates to the subscribing RQP (e.g. sending updatesto table size as it changes).

FIG. 8 is a flowchart of an example method 800 of processing a columnlocation metadata retrieval request by a TDCP server (e.g., as shown inFIG. 3B or FIG. 4) in accordance with some implementations. Processingbegins at 802, where a remote query processor (RQP) (e.g., remote queryprocessors 132-134, 322, 372-376, or 412-414 shown in FIG. 1, FIG. 3A,3B, and FIG. 4, respectively) requests column location metadata (e.g.,grouping information, periodic/historical). Processing continues to 804.

At 804, the TDCP determines whether the requested column locationmetadata is in the TDCP local state (or cache such as, e.g., shared RAM336, shared memory 384, or cache 406 shown in FIG. 3A, FIG. 3B, and FIG.4, respectively). If so, processing continues to 810; otherwise,processing continues to 806.

At 806 the TDCP requests column location metadata from one or moreappropriate data servers (e.g., LTDS 124, DIS 120, and/or RUTS 142 shownin FIG. 1 and FIG. 4) and optionally subscribes for updates. Forexample, a subscriber could subscribe to receive updates to valueindexes included in column metadata (e.g., forreal-time/periodic/intraday data). In some embodiments, the TDCP iscoupled to multiple data servers (e.g., LTDS 124, DIS 120, and/or RUTS142) and the TDCP selects one or more of the multiple data servers asthe appropriate data servers for the request received at 802. In someembodiments, the one or more appropriate data servers can be selectedbased on the table type indicated by a table type and/or table locationindicated in the request received at 802 (e.g., by determining which ofthe data servers match the table type and/or table location andselecting those that match).

At 808, the TDCP receives column location metadata. The column locationmetadata is received in response to the request(s) made by the TDCP at806 and are stored in the TDCP cache. Processing continues to 810.

At 810, the TDCP filters/distributes the column location metadata to theRQP. The column location metadata can be filtered based on rules suchas, for example, rules defining where data should come from (e.g., whichdata source is authoritative). Column location metadata can also befiltered to eliminate updates of a nature not needed/requested bycertain downstream consumers (e.g., grouping/indexing changes if theRQP/query doesn't use them), in some embodiments, filtering at 810 caninclude removing metadata changes that aren't important to certainclasses of downstream consumers (e.g., some TDCPs or RQPs might onlywant size changes, and/or might not want modifications after a certaintime of day, and/or might not need to see all metadata fields).Additionally or alternatively, the TDCP can combine data related to twoor more “downstream” table locations (with the same keys), and filteringat 810 can include coalescing changes and only advertising them when(for example) a threshold (more than one, or all) number of the datasources being combined had advertised the same thing, thereby increasingthe likelihood that data can be re-read promptly in the event of asubset of the data sources crashing or becoming partitioned away.Processing continues to 812.

At 812, the TDCP listens to table updates from the data servers.Listening to table updates can include listening to table updates fromdata servers to which the TDCP has subscribed for updates. Processingcontinues to 814.

At 814, the TDCP distributes updates to subscribing RQP. The TDCP canoperate as an aggregator of subscriptions for multiple RQP and uponreceiving an update the TDCP can distribute the update to thesubscribing RQP. For example, although not shown, two different RQP cansubscribe to the TDCP to receive updates to column location metadata. Insome embodiments, the updates can be filtered as described above at 810before being distributed to subscribing RQP.

It will be appreciated that, although not shown, the subscribing RQP cancancel their subscription to stop receiving updates from the TDCP, thatall subscriptions are cancelled for an RQP that disconnects, and thatthe TDCP may cancel its own data subscriptions and/or discard data it nolonger needs for any RQP.

It will also be appreciated that 802-814 may be repeated in whole or inpart. For example, 812-814 may be repeated to continuously providecolumn location metadata updates to the subscribing RQP (e.g. sendingupdated column size as it changes)

FIG. 9 is a flowchart of an example method 900 of processing a columnfile metadata retrieval request by a TDCP server (e.g., as shown in FIG.3B or FIG. 4) in accordance with some implementations. Processing beginsat 902, where a remote query processor (RQP) (e.g., remote queryprocessors 132-134, 322, 372-376, or 412-414 shown in FIG. 1, FIG. 3A,FIG. 3B, and FIG. 4, respectively) requests column file metadata whichcan include column file size e.g., for column files that aren't an exactmultiple of table location size) from the TDCP. Processing continues to904.

At 904, the TDCP determines whether the requested column file metadatais in the TDCP local state (or cache such as, e.g., shared RAM 336,shared memory 384, or cache 406 shown in FIG. 3A, FIG. 3B, and FIG. 4,respectively). If so, processing continues to 910; otherwise, processingcontinues to 906.

At 906 the TDCP requests column file metadata from one or moreappropriate data servers (e.g., LTDS 124, DIS 120, and/or RUTS 142 shownin FIG. 1 and FIG. 4) and optionally subscribes for updates. In someembodiments, the TDCP is coupled to multiple data servers e.g., LTDS124, DIS 120, and/or RUTS 142) and the TDCP selects one or more of themultiple data servers as the appropriate data servers for the requestreceived at 902. In some embodiments, the one or more appropriate dataservers can be selected based on a column and/or column location/fileindicated in the request received at 902 (e.g., by determining which ofthe data servers match the column and/or column location/file).

At 908, the TDCP receives column file metadata. The column file metadatais received in response to the request(s) made by the TDCP at 906 andare stored in the TDCP cache. Processing continues to 910.

At 910, the TDCP filters/distributes the column file metadata to theRQP. The column file metadata can be filtered based on rules such as,for example, rules defining where data should come from (e.g., whichdata source is authoritative). Column file metadata can be filtered, forexample, to throttle the rate of change notification to the samefrequency as other notifications such as table metadata (e.g., size)change notifications. Column file metadata can also be filtered toeliminate updates of a nature not needed/requested by certain downstreamconsumers. In some embodiments, filtering at 910 can include removingmetadata changes that aren't important to certain classes of downstreamconsumers (e.g., some TDCPs or RQPs might not want modifications after acertain time of day, and/or might not need to see all metadata fields).Additionally or alternatively, the TDCP can combine data related to twoor more “downstream” table locations (with the same keys), and filteringat 910 can include coalescing changes and only advertising them when(for example) a threshold (more than one, or all) number of the datasources being combined had advertised the same thing, thereby increasingthe likelihood that data can be re-read promptly in the event of asubset of the data sources crashing or becoming partitioned away.Processing continues to 912.

At 912, the TDCP listens to table updates from the data servers.Listening to table updates can include listening to table updates fromdata servers to which the TDCP has subscribed for updates. Processingcontinues to 914.

At 914, the TDCP distributes updates to subscribing RQP. The TDCP canoperate as an aggregator of subscriptions for multiple RQP and uponreceiving an update the TDCP can distribute the update to thesubscribing RQP. For example, although not shown, two different RQP cansubscribe to the TDCP to receive updates to column file metadata. Insome embodiments, the updates can be filtered as described above at 910before being distributed to subscribing RQP.

It will be appreciated that, although not shown, the subscribing RQP cancancel their subscription to stop receiving updates from the TDCP, thatall subscriptions are cancelled for an RQP that disconnects, and thatthe TDCP may cancel its own data subscriptions and/or discard data it nolonger needs for any RQP.

It will also be appreciated that 902-914 may be repeated in whole or inpart. For example, 912-914 may be repeated to continuously providecolumn file size updates to the subscribing RQP (e.g. sending updatedcolumn size as it changes).

FIG. 10 is a flowchart of an example method 1000 of processing a columnfile data. retrieval request by a TDCP server (e.g., as shown in FIG. 3Bor FIG. 4) in accordance with some implementations. Processing begins at1002, where a remote query processor (RQP) (e.g., remote queryprocessors 132-134, 322, 372-376, or 412-414 shown in FIG. 1, FIG. 3A,FIG. 3B, and FIG. 4, respectively) requests column file data from theTDCP. The client, and each intermediating service that cannot satisfythe request out of cache, requests the data for a block of binary data.The request includes the block size (which may be standardized at theservice level), starting offset of the block within the column file,starting offset desired within the block, and minimum result length.More data (e.g., up to the maximum result length=block size−startingoffset within the block) may be retrieved if available to preventredundant subsequent requests. Processing continues to 1004.

At 1004, the TDCP determines whether the column file data is in the TDCPlocal state (or cache such as, e.g., shared RAM 336, shared memory 384,or cache 406 shown in FIG. 3A, FIG. 3B, and FIG. 4, respectively). Ifso, processing continues to 1010; otherwise, processing continues to1006.

At 1006 the TDCP requests column file data from one or more appropriatedata servers (e.g., LTDS 124, DIS 120, and/or RUTS 142 shown in FIG. 1and FIG. 4) and optionally subscribes for updates. In some embodiments,the TDCP is coupled to multiple data servers e.g., LTDS 124, DIS 120,and/or RUTS 142) and the TDCP selects one or more of the multiple dataservers as the appropriate data servers for the request received at1002. In some embodiments, the one or more appropriate data servers canbe selected based on the column file and/or the type of table that thecolumn is a part of (e.g., by determining which of the data serversmatch the table type and selecting those that match). In someembodiments, when the TDCP has only a portion of the requested data incache the TDCP can request whatever sub-range it doesn't have, and eachrequest might actually get more data than they asked for in order toamortize away subsequent requests.

At 1008, the TDCP receives column file data. The column file data isreceived in response to the request(s) made by the TDCP at 1006 and arestored in the TDCP cache. Processing continues to 1010.

At 1010, the TDCP filters responses and/or distributes the column filedata to the RQP. The column file data can be filtered based on rulessuch as, for example, rules defining where data should come from (e.g.,which data source is authoritative when the data was requested from twoor more sources). In some embodiments, the TDCP can be configured tooptimize the performance of computer data access when multiple dataservers each provide access to the same data by requesting differentportions of the requested column file data from two or more of themultiple data servers at 606 and by filtering the responses to combinethe different portions of column file data received from the multipledata servers into the column file data to be distributed to the RQP. Insuch embodiments, the TDCP can, for example, split the request acrossthe multiple data servers, thereby distributing data access across themultiple data servers. In some embodiments, the TDCP or RQP maydetermine that requests for column file data follow a pattern (e.g.,sequential access, striding, etc.) and prefetch one or more additionalblocks or ranges of column file data from the appropriate data sourcesin order to enhance system performance by decreasing perceived latencyand/or amortizing request costs. Processing continues to 1012.

At 1012, the TDCP listens to table updates from the data servers.Listening to table updates can include listening to table updates fromdata servers to which the TDCP has subscribed for updates. Processingcontinues to 1014.

At 1014, the TDCP distributes updates to subscribing RQP. The TDCP canoperate as an aggregator of subscriptions for multiple RQP and uponreceiving an update the TDCP can distribute the update to thesubscribing RQP. For example, although not shown, two different RQP cansubscribe to the TDCP to receive updates. In some embodiments, theupdates can be filtered as described above at 1010 before beingdistributed to subscribing RQP.

It will be appreciated that, although not shown, the subscribing RQP cancancel their subscription to stop receiving updates from the TDCP, thatall subscriptions are cancelled for an RQP that disconnects, and thatthe TDCP may cancel its own data subscriptions and/or discard data it nolonger needs for any RQP.

It will also be appreciated that 1002-1014 may be repeated in whole orin part. For example, 1012-1014 may be repeated to continuously providetable location updates to the subscribing RQP.

FIG. 11 is a diagram of an example computing device 300 configured fortable data cache proxy (TDCP) processing in accordance with at least oneimplementation. The computing device 300 includes one or more processors302, operating system 304, computer readable medium 306 and networkinterface 308. The memory 306 can include table data cache proxy (TDCP)application 310 and a data section 312 (e.g., for storing caches, indexdata structures, column source maps, etc.).

In operation, the processor 302 may execute the application 310 storedin the memory 306. The application 310 can include software instructionsthat, when executed by the processor, cause the processor to performoperations for table data cache proxy processing in accordance with thepresent disclosure performing one or more of 502-514, 602-614, 702-714,802-814, 902-914, and/or 1002-1014 described above).

The application program 310 can operate in conjunction with the datasection 312 and operating system 304.

Although references have been made herein to tables and table data, itwill be appreciated that the disclosed systems and methods can beapplied with various computer data objects to, for example, provideflexible data routing and caching for such objects in accordance withthe disclosed subject matter. For example, references herein to tablescan include a collection of objects generally, and tables can includecolumn types that are not limited to scalar values and can includecomplex types (e.g., objects).

It will be appreciated that the modules, processes, systems, andsections described above can be implemented in hardware, hardwareprogrammed by software, software instructions stored on a nontransitorycomputer readable medium or a combination of the above. A system asdescribed above, for example, can include a processor configured toexecute a sequence of programmed instructions stored on a nontransitorycomputer readable medium. For example, the processor can include, butnot be limited to, a personal computer or workstation or other suchcomputing system that includes a processor, microprocessor,microcontroller device, or is comprised of control logic includingintegrated circuits such as, for example, an Application SpecificIntegrated Circuit (ASIC), afield programmable gate array (FPGA), agraphics processing unit (e.g., GPGPU or GPU) or the like. Theinstructions can be compiled from source code instructions provided inaccordance with a programming language such as Java, C, C++, C#.net,assembly or the like. The instructions can also comprise code and dataobjects provided in accordance with, for example, the Visual Basiclanguage, a specialized database query language, or another structuredor object-oriented programming language. The sequence of programmedinstructions, or programmable logic device configuration software, anddata associated therewith can be stored in a nontransitorycomputer-readable medium such as a computer memory or storage devicewhich may be any suitable memory apparatus, such as, but not limited toROM, PROM, EEPROM, RAM, flash memory, disk drive and the like.

Furthermore, the modules, processes systems, and sections can beimplemented as a single processor or as a distributed processor.Further, it should be appreciated that the steps mentioned above may beperformed on a single or distributed processor (single and/ormulti-core, or cloud computing system). Also, the processes, systemcomponents, modules, and sub-modules described in the various figures ofand for embodiments above may be distributed across multiple computersor systems or may be co-located in a single processor or system. Examplestructural embodiment alternatives suitable for implementing themodules, sections, systems, means, or processes described herein areprovided below.

The modules, processors or systems described above can be implemented asa programmed general purpose computer, an electronic device programmedwith microcode, a hard-wired analog logic circuit, software stored on acomputer-readable medium or signal, an optical computing device, anetworked system of electronic and/or optical devices, a special purposecomputing device, an integrated circuit device, a semiconductor chip,and/or a software module or object stored on a computer-readable mediumor signal, for example.

Embodiments of the method and system (or their sub-components ormodules), may be implemented on a general-purpose computer, aspecial-purpose computer, a programmed microprocessor or microcontrollerand peripheral integrated circuit element, an ASIC or other integratedcircuit, a digital signal processor, a hardwired electronic or logiccircuit such as a discrete element circuit, a programmed logic circuitsuch as a PLD, PLA, FPGA, PAL, GP, GPU, or the like. In general, anyprocessor capable of implementing the functions or steps describedherein can be used to implement embodiments of the method, system, or acomputer program product (software program stored on a nontransitorycomputer readable medium).

Furthermore, embodiments of the disclosed method, system, and computerprogram product (or software instructions stored on a nontransitorycomputer readable medium) may be readily implemented, fully orpartially, in software using, for example, object or object-orientedsoftware development environments that provide portable source code thatcan be used on a variety of computer platforms. Alternatively,embodiments of the disclosed method, system, and computer programproduct can be implemented partially or fully in hardware using, forexample, standard logic circuits or a VLSI design. Other hardware orsoftware can be used to implement embodiments depending on the speedand/or efficiency requirements of the systems, the particular function,and/or particular software or hardware system, microprocessor, ormicrocomputer being utilized. Embodiments of the method, system, andcomputer program product can be implemented in hardware and/or softwareusing any known or later developed systems or structures, devices and/orsoftware by those of ordinary skill in the applicable art from thefunction description provided herein and with a general basic knowledgeof the software engineering and computer networking arts.

Moreover, embodiments of the disclosed method, system, and computerreadable media (or computer program product) can be implemented insoftware executed on a programmed general purpose computer, a specialpurpose computer, a microprocessor, or the like.

It is, therefore, apparent that there is provided, in accordance withthe various embodiments disclosed herein, methods, systems and computerreadable media for computer data distribution architecture.

Application Ser. No. ______, entitled “DATA PARTITIONING AND ORDERING”(Attorney Docket No. W1.1-10057) and filed in the United States Patentand Trademark Office on May 14, 2016, is hereby incorporated byreference herein in its entirety as if fully set forth herein.

Application Ser. No. ______, entitled “COMPUTER DATA SYSTEM DATA SOURCEREFRESHING USING AN UPDATE PROPAGATION GRAPH” (Attorney Docket No.W1.4-10058) and filed in the United States Patent and Trademark Officeon May 14, 2016, is hereby incorporated by reference herein in itsentirety as if fully set forth herein.

Application Ser. No. ______, entitled “COMPUTER DATA SYSTEMPOSITION-INDEX MAPPING” (Attorney Docket No. W1.5-10083) and filed inthe United States Patent and Trademark Office on May 14, 2016, is herebyincorporated by reference herein in its entirety as if fully set forthherein.

Application Ser. No. ______, entitled “SYSTEM PERFORMANCE LOGGING OFCOMPLEX REMOTE QUERY PROCESSOR QUERY OPERATIONS” (Attorney Docket No.W1.6-10074) and filed in the United States Patent and Trademark Officeon May 14, 2016, is hereby incorporated by reference herein in itsentirety as if fully set forth herein.

Application Ser. No. ______, entitled “DISTRIBUTED AND OPTIMIZED GARBAGECOLLECTION OF REMOTE AND EXPORTED TABLE HANDLE LINKS TO UPDATEPROPAGATION GRAPH NODES” (Attorney Docket No. W1.8-10085) and filed inthe United States Patent and Trademark Office on May 14, 2016, is herebyincorporated by reference herein in its entirety as if fully set forthherein.

Application Ser. No. ______, entitled “COMPUTER DATA SYSTEM CURRENT ROWPOSITION QUERY LANGUAGE CONSTRUCT AND ARRAY PROCESSING QUERY LANGUAGECONSTRUCTS” (Attorney Docket No. W2.1-10060) and filed in the UnitedStates Patent and Trademark Office on May 14, 2016, is herebyincorporated by reference herein in its entirety as if fully set forthherein.

Application Ser. No. ______, entitled “PARSING AND COMPILING DATA SYSTEMQUERIES” (Attorney Docket No. W2.2-10062) and filed in the United StatesPatent and Trademark Office on May 14, 2016, is hereby incorporated byreference herein in its entirety as if fully set forth herein.

Application Ser. No. ______, entitled “DYNAMIC FILTER PROCESSING”(Attorney Docket No, W2.4-10075) and filed in the United States Patentand Trademark Office on May 14, 2016, is hereby incorporated byreference herein in its entirety as if fully set forth herein.

Application Ser. No. ______, entitled “DYNAMIC JOIN PROCESSING USINGREAL-TIME MERGED NOTIFICATION LISTENER” (Attorney Docket No. W2.6-10076)and filed in the United States Patent and Trademark Office on May 14,2016, is hereby incorporated by reference herein in its entirety as iffully set forth herein.

Application Ser. No. ______, entitled “DYNAMIC TABLE INDEX MAPPING”(Attorney Docket No. W2.7-10077) and filed in the United States Patentand Trademark Office on May 14, 2016, is hereby incorporated byreference herein in its entirety as if fully set forth herein.

Application Ser. No. ______, entitled “QUERY TASK PROCESSING BASED ONMEMORY ALLOCATION AND PERFORMANCE CRITERIA” (Attorney Docket No.W2.8-10094) and filed in the United States Patent and Trademark Officeon May 14, 2016, is hereby incorporated by reference herein in itsentirety as if fully set forth herein.

Application Ser. No. ______, entitled “A MEMORY-EFFICIENT COMPUTERSYSTEM FOR DYNAMIC UPDATING OF JOIN PROCESSING” (Attorney Docket No.W2.9-10107) and filed in the United States Patent and Trademark Officeon May 14, 2016, is hereby incorporated by reference herein in itsentirety as if fully set forth herein.

Application Ser. No. ______, entitled “QUERY DISPATCH AND EXECUTIONARCHITECTURE” (Attorney Docket No. W3.1-10061) and filed in the UnitedStates Patent and Trademark Office on May 14, 2016, is herebyincorporated by reference herein in its entirety as if fully set forthherein.

Application Ser. No. ______, entitled “COMPUTER DATA DISTRIBUTIONARCHITECTURE” (Attorney Docket No. W3.2-10087) and filed in the UnitedStates Patent and Trademark Office on May 14, 2016, is herebyincorporated by reference herein in its entirety as if fully set forthherein.

Application Ser. No. ______, entitled “DYNAMIC UPDATING OF QUERY RESULTDISPLAYS” (Attorney Docket No. W3.3-10059) and filed in the UnitedStates Patent and Trademark Office on May 14, 2016, is herebyincorporated by reference herein in its entirety as if fully set forthherein.

Application Ser. No. ______, entitled “DYNAMIC CODE LOADING” (AttorneyDocket No. W3.4-10065) and filed in the United States Patent andTrademark Office on May 14, 2016, is hereby incorporated by referenceherein in its entirety as if fully set forth herein.

Application Ser. No. ______, entitled “IMPORTATION, PRESENTATION, ANDPERSISTENT STORAGE OF DATA” (Attorney Docket No. W3.5-10088) and filedin the United States Patent and Trademark Office on May 14, 2016, ishereby incorporated by reference herein in its entirety as if fully setforth herein.

Application Ser. No. ______, entitled “COMPUTER DATA DISTRIBUTIONARCHITECTURE” (Attorney Docket No. W3.7-10079) and filed in the UnitedStates Patent and Trademark Office on May 14, 2016, is herebyincorporated by reference herein in its entirety as if fully set forthherein.

Application Ser. No. ______, entitled “PERSISTENT QUERY DISPATCH ANDEXECUTION ARCHITECTURE” (Attorney Docket No. W4.2-10089) and filed inthe United States Patent and Trademark Office on May 14, 2016, is herebyincorporated by reference herein in its entirety as if fully set forthherein.

Application Ser. No. ______, entitled “SINGLE INPUT GRAPHICAL USERINTERFACE CONTROL ELEMENT AND METHOD” (Attorney Docket No. W4.3-10063)and filed in the United States Patent and Trademark Office on May 14,2016, is hereby incorporated by reference herein in its entirety as iffully set forth herein.

Application Ser. No. ______, entitled “GRAPHICAL USER INTERFACE DISPLAYEFFECTS FOR A COMPUTER DISPLAY SCREEN” (Attorney Docket No. W4.4-10090)and filed in the United States Patent and Trademark Office on May 14,2016, is hereby incorporated by reference herein in its entirety as iffully set forth herein.

Application Ser. No. ______, entitled “COMPUTER ASSISTED COMPLETION OFHYPERLINK COMMAND SEGMENTS” (Attorney Docket No. W4.5-10091) and filedin the United States Patent and Trademark Office on May 14, 2016, ishereby incorporated by reference herein in its entirety as if fully setforth herein.

Application Ser. No. ______, entitled “HISTORICAL DATA REPLAY UTILIZINGA COMPUTER SYSTEM” (Attorney Docket No. W5.1-10080) and filed in theUnited States Patent and Trademark Office on May 14, 2016, is herebyincorporated by reference herein in its entirety as if fully set forthherein.

Application Ser. No. ______, entitled DATA STORE ACCESS PERMISSIONSYSTEM WITH INTERLEAVED APPLICATION OF DEFERRED ACCESS CONTROL FILTERS″(Attorney Docket No. W6.1-10081) and filed in the United States Patentand Trademark Office on May 14, 2016, is hereby incorporated byreference herein in its entirety as if fully set forth herein.

Application Ser. No. ______, entitled “REMOTE DATA OBJECTPUBLISHING/SUBSCRIBING SYSTEM HAVING A MULTICAST KEY-VALUE PROTOCOL”(Attorney Docket No. W7.2-10064) and filed in the United States Patentand Trademark Office on May 14, 2016, is hereby incorporated byreference herein in its entirety as if fully set forth herein.

While the disclosed subject matter has been described in conjunctionwith a number of embodiments, it is evident that many alternatives,modifications and variations would be, or are, apparent to those ofordinary skill in the applicable arts. Accordingly, Applicants intend toembrace all such alternatives, modifications, equivalents and variationsthat are within the spirit and scope of the disclosed subject matter.

What is claimed is:
 1. A memory-efficient and processor-efficientcomputer system for reliable implementation of a table data cache proxy,the system comprising: a plurality of data server computers each beingprogrammed with a table data service accessible via an electronicmessaging protocol; a table data cache proxy enabled (TDCP-enabled)server computer coupled to the one or more data server computers, theTDCP-enabled server computer having a plurality of TDCP clients, theTDCP-enabled server computer caching data from the plurality of dataserver computers and aggregating subscriptions of the TDCP clients tothe plurality of data server computers; the TDCP-enabled server computercomprising: one or more hardware processors; a cache memory devicehaving at least a portion being a shared memory portion; and a computerreadable data storage device coupled to the one or more hardwareprocessors, the computer readable data storage device having storedthereon software instructions that, when executed by the one or morehardware processors, cause the one or more hardware processors toperform operations including: receiving, from a first TDCP client of theplurality of TDCP clients, a first electronic message requesting tabledata; determining whether a shared memory cache stored in the sharedmemory portion of the cache memory device contains a cached copy of therequested table data; when the shared memory cache contains a cachedcopy of the requested table data, transmitting, to the first TDCPclient, one or more second electronic messages comprising a referenceindicating a location were the cached copy is stored in the sharedmemory portion of the cache memory device in response to the firstelectronic message, the data received from at least one of the pluralityof data server computers and stored in the cache memory device beingauthoritative due to a data model of the plurality of data servercomputers; when the shared memory cache does not contain a cached copyof the requested table data: selecting one or more data server computersfrom the plurality of data server computers as one or more appropriatedata server computers to provide the requested table data, transmittingone or more third electronic messages to the one or more appropriatedata server computers requesting the requested table data, receiving oneor more fourth electronic messages from the one or more appropriate dataserver computers in response to the third electronic messages, filteringthe received fourth electronic messages and storing a result of thefiltering in the shared memory portion of the cache memory device, andtransmitting, to the first TDCP client computer, one or more fifthelectronic messages comprising a reference indicating a location wherethe result of the filtering is stored in the shared memory portion ofthe cache memory device in response to the first electronic message. 2.The system of claim 1, wherein the operations further include: when theshared memory cache does not contain a cached copy of the requestedtable data, transmitting a request to subscribe for updates from the oneor more appropriate data server computers; receiving a subscriptionupdate from one or more of the plurality of data server computers; andelectronically distributing the received subscription update to one ormore of the plurality of TDCP clients.
 3. The system of claim 1, whereinthe first electronic message requests data from a data block andcomprises a minimum response length; and wherein, when additional dataabove the minimum response length is available within the block, theadditional data is included in response to the first electronic messageto prevent redundant subsequent requests.
 4. The system of claim 1,wherein the first electronic message includes a table location discoveryrequest requesting a list of table locations for a given table key, thetable key uniquely identifying a table.
 5. The system of claim 1,wherein the first electronic message is a table location metadataretrieval request requesting table-location-level metadata including thesize of a table.
 6. The system of claim 1, wherein the first electronicmessage is a column location metadata retrieval request requestingcolumn-location-level metadata.
 7. The system of claim 1, wherein columndata is laid out in an optimized data layout to enable high performancedata access, the column-location-level metadata including informationindicating the optimized data layout.
 8. The system of claim 1, whereinthe first electronic message is a column file size retrieval requestrequesting the size of a column file.
 9. The system of claim 1, whereinthe first electronic message is a column file data retrieval requestrequesting at least a portion of a block of binary data from a columnfile.
 10. The system of claim 1, wherein the plurality of data servercomputers comprises at least two data server computers providing thesame data; and wherein the TDCP-enabled server is configured toreconnect to any of the data server computers, and upon reconnection anyin-progress requests are re-sent and any subscriptions are renewed. 11.The system of claim 1, wherein the operations further include: when thefirst electronic message requests a block of binary data, determiningwhether a future request for another block of binary data is likelybased on a number of previously received requests; and when the futurerequest is determined to be likely, prefetching the another block ofbinary data including transmitting one or more sixth electronic messagesto the one or more appropriate data servers requesting the another blockof binary data.
 12. A memory-efficient and processor-efficient computersystem for reliable implementation of a table data cache proxy, thesystem comprising: at least one data server having a table data serviceaccessible via an electronic messaging protocol; a table data cacheproxy enabled (TDCP-enabled) server coupled to the one or more dataservers, the TDCP-enabled server caching data from the plurality of dataservers and aggregating subscriptions to the plurality of data servers;the TDCP-enabled server comprising: one or more hardware processors; acomputer readable data storage device coupled to the one or morehardware processors, the computer readable data storage device havingstored thereon software instructions that, when executed by the one ormore hardware processors, cause the one or more hardware processors toperform operations including: receiving a first electronic messagerequesting table data; determining whether a cache of the TDCP-enabledserver contains a cached copy of the requested table data; when thecache of the TDCP-enabled server contains a cached copy of the requestedtable data, transmitting one or more second electronic messagesproviding the cached copy of the requested table data from the cache inresponse to the first electronic message, the data received from atleast one of the plurality of data servers and stored in the cache beingauthoritative due to a data model of the plurality of data servers; whenthe cache of the TDCP-enabled server does not contain a cached copy ofthe requested data: determining one or more appropriate data servers ofthe plurality of data servers to request the requested table data from,transmitting one or more third electronic messages to the one or moreappropriate data servers requesting the requested table data, receivingone or more fourth electronic messages from the one or more appropriateservers in response to the one or more third electronic messages, andfiltering the received one or more fourth electronic messages and, basedon a result of the filtering, transmitting one or more fifth electronicmessages providing the requested table data in response to the firstelectronic message.
 13. The system of claim 12, wherein the TDCP-enabledserver further comprises a shared memory in which at least a portion ofthe cache is stored, wherein the one or more second electronic messagescomprise an indication where the cached copy is stored in the sharedmemory of the TDCP-enabled server, and wherein the one or more fifthelectronic messages comprise indications where the requested table datais stored in the shared memory of the TDCP-enabled server.
 14. Thesystem of claim 12, wherein the first electronic message is received viaa network from a remote client, the one or more second electronicmessages are transmitted to the remote client via the network, and theone or more fifth electronic messages are transmitted to the remoteclient via the network.
 15. The system of claim 12, wherein the firstelectronic message is received via an inter process communication (IPC)mechanism from a client, the one or more second electronic messages aretransmitted to the client via the IPC mechanism, and the one or morefifth electronic messages are transmitted to the client via the IPCmechanism.
 16. The system of claim 12, wherein the first electronicmessage requests data from a data block and comprises a minimum responselength; and wherein, when additional data above the minimum responselength is available within the block, the additional data is included inresponse to the first electronic message to prevent redundant subsequentrequests.
 17. The system of claim 12, wherein the first electronicmessage is one of: a table location discovery request requesting a listof table locations for a given table key, the table key uniquelyidentifying a table; a table location metadata retrieval requestrequesting table-location-level metadata including the size of a table;a column location metadata retrieval request requestingcolumn-location-level metadata, wherein column data is laid out in anoptimized data layout to enable high performance data access, thecolumn-location-level metadata including information indicating theoptimized data layout; a column file size retrieval request requestingthe size of a column file; and a column file data retrieval requestrequesting at least a portion of a block of binary data from a columnfile.
 18. The system of claim 12, wherein the at least one data serveris a plurality of data servers comprising at least two data sourcesproviding the same data; and wherein the TDCP-enabled server isconfigured to reconnect to any of the data servers, and uponreconnection any in-progress requests are re-sent and any subscriptionsare renewed.
 19. The system of claim 12, wherein the operations furtherinclude: when the first electronic message requests a block of binarydata, determining whether a future request for another block of binarydata is likely based on a number of received requests; and when thefuture request is determined to be likely, prefetching the another blockof binary data including transmitting one or more sixth electronicmessages to the one or more appropriate data servers requesting theanother block of binary data.
 20. A memory-efficient andprocessor-efficient computerized method for reliable implementation of atable data cache proxy, the method comprising: receiving, at a tabledata cache proxy enabled (TDCP-enabled) server, a first electronicmessage requesting table data, the TDCP-enabled server being coupled toone or more data servers having a table data service accessible via anelectronic messaging protocol, the TDCP-enabled server caching data fromthe one or more data servers and aggregating subscriptions to the one ormore data servers; determining whether a cache of the TDCP-enabledserver contains a cache copy of the requested table data; when the cacheof the TDCP-enabled server contains a cached copy of the requested tabledata, transmitting one or more second electronic messages providing thecached copy of the requested table data from the cache in response tothe first electronic message, the data received from at least one of theone or more data servers and stored in the cache being authoritative dueto a data model of the one or more data servers; when the cache of theTDCP-enabled server does not contain a cached copy of the requesteddata: determining one or more appropriate data servers of the one ormore data servers to request the requested table data from, transmittingone or more third electronic messages to the one or more appropriatedata servers requesting the requested table data, receiving one or morefourth electronic messages from the one or more appropriate servers inresponse to the one or more third electronic messages, and filtering thereceived one or more fourth electronic messages and, based on a resultof the filtering, transmitting one or more fifth electronic messagesproviding the requested table data in response to the first electronicmessage.
 21. The method of claim 20, wherein the one or more dataservers comprises a plurality of data servers; and wherein, when thefirst electronic message requests one or more data locations, thefiltering comprises combining at least a portion of each of two or moreof the one or more fourth electronic messages to create a composite ofdata from two or more of the plurality of data servers as the result ofthe filtering.
 22. The method of claim 20, wherein the first electronicmessage is one of: a table location discovery request requesting a listof table locations for a given table key, the table key uniquelyidentifying a table; a table location metadata retrieval requestrequesting table-location-level metadata including the size of a table;a column location metadata retrieval request requestingcolumn-location-level metadata, wherein column data is laid out in anoptimized data layout to enable high performance data access, thecolumn-location-level metadata including information indicating theoptimized data layout; a column file size retrieval request requestingthe size of a column file; and a column file data retrieval requestrequesting at least a portion of a block of binary data from a columnfile.
 23. The method of claim 20, wherein the one or more data serverscomprises a plurality of data servers comprising a first and second dataserver providing the same data; and wherein the TDCP-enabled server isconfigured to reconnect to any of the data servers, and uponreconnection any in-progress requests are re-sent and any subscriptionsare renewed.
 24. The method of claim 20, further comprising: determiningwhether a future request for another block of binary data is likelybased on a number of received requests; and when the future request isdetermined to be likely, prefetching the another block of binary dataincluding transmitting one or more sixth electronic messages to the oneor more appropriate data servers requesting the another block of binarydata.
 25. The method of claim 20, further comprising: when the cache ofthe TDCP-enabled server does not contain a cached copy of the requesteddata, transmitting a request to subscribe for updates from the one ormore appropriate data servers; receiving a subscription update from oneor more of the one or more data servers; and electronically distributingthe received subscription update to one or more subscribers of theTDCP-enabled server.
 26. A non transitory computer readable mediumhaving stored thereon software instructions that, when executed by oneor more processors, cause the one or more processors to performoperations including: receiving, at a table data cache proxy enabled(TDCP-enabled) server, a first electronic message requesting table data,the TDCP-enabled server being coupled to one or more data servers havinga table data service accessible via an electronic messaging protocol,the TDCP-enabled server caching data from the one or more data serversand aggregating subscriptions to the one or more data servers;determining whether a cache of the TDCP-enabled server contains a cachedcopy of the requested table data; when the cache of the TDCP-enabledserver contains a cached copy of the requested table data, transmittingone or more second electronic messages providing the cached copy of therequested table data from the cache in response to the first electronicmessage, the data received from at least one of the one or more dataservers and stored in the cache being authoritative due to a data modelof the one or more data servers; when the cache of the TDCP-enabledserver does not contain a cached copy of the requested data: determiningone or more appropriate data servers of the one or more data servers torequest the requested table data from, transmitting one or more thirdelectronic messages to the one or more appropriate data serversrequesting the requested table data, receiving one or more fourthelectronic messages from the one or more appropriate servers in responseto the one or more third electronic messages, and filtering the receivedone or more fourth electronic messages and, based on a result of thefiltering, transmitting one or more fifth electronic messages providingthe requested table data in response to the first electronic message.27. The nontransitory computer readable medium of claim 26, theoperations further comprising: wherein the one or more data serverscomprises a plurality of data servers; and wherein, when the firstelectronic message requests one or more data locations, the filteringcomprises combining at least a portion of each of two or more of the oneor more fourth electronic messages to create a composite of data fromtwo or more of the plurality of data servers as the result of thefiltering.
 28. The nontransitory computer readable medium of claim 26,wherein the first electronic message is one of: a table locationdiscovery request requesting a list of table locations for a given tablekey, the table key uniquely identifying a table; a table locationmetadata retrieval request requesting table-location-level metadataincluding the size of a table; a column location metadata retrievalrequest requesting column-location-level metadata, wherein column datais laid out in an optimized data layout to enable high performance dataaccess, the column-location-level metadata including informationindicating the optimized data layout; a column file size retrievalrequest requesting the size of a column file; and a column file dataretrieval request requesting at least a portion of a block of binarydata from a column file.
 29. The nontransitory computer readable mediumof claim 26, wherein the one or more data servers comprises a pluralityof data servers comprising a first and second data server providing thesame data; and wherein the TDCP-enabled server is configured toreconnect to any of the data servers, and upon reconnection anyin-progress requests are re-sent and any subscriptions are renewed. 30.The nontransitory computer readable medium of claim 26, the operationsfurther comprising: determining whether a future request for anotherblock of binary data is likely based on a number of received requests;and when the future request is determined to be likely, prefetching theanother block of binary data including transmitting one or more sixthelectronic messages to the one or more appropriate data serversrequesting the another block of binary data.